Linearly polarized light backscattered from weakly scattering slabs in the cross-polarized channel manifests a symmetrical pattern. The origin and the properties of the pattern are explained and how it can be used to extract the average pathlength of the photons in the medium is shown. It is also shown that the concentration of scatterers rather than the optical depth of the sample determines the properties of the crosspolarized backscattered light.
"Photon pathlength distribution from polarized backscattering in random media," Optical Engineering 35(8), (1 August 1996). https://doi.org/10.1117/1.601016